Improving the activity of rutile titanium dioxide with reduced graphene oxide

Abstract

Among titanium dioxide (TiO2), rutile is the most stable polymorph of TiO2 at all temperatures. However, its application as photocatalyst is less explored since generally anatase and anatase-rutile mixture show better photocatalytic activity than the rutile structure. In this study, we successfully improved the photocatalytic activity of rutile up to four times higher when it was modified with reduced graphene oxide (rGO). The rGO-TiO2 composites were prepared by photocatalytic reduction of graphene oxide (GO) at room temperature under ultraviolet (UV) light irradiation in the presence of rutile TiO2. The amount of GO which was prepared by oxidation of graphite flakes via the Hummers’ method was varied from 0.5 to 5 wt%. The properties of the obtained composites were investigated by several characterization methods. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopies revealed that the rGO-TiO2 composites could be prepared without disrupting the structure of rutile TiO2. The fluorescence spectroscopy confirmed that the presence of rGO decreased the emission intensity of rutile TiO2, suggesting that the interactions between the rGO and the rutile TiO2 might cause the decrease in electron-hole recombination on the TiO2. The activity of the composites was evaluated for degradation of phenol under UV light irradiation for 3 h. It was observed that the addition of small amount of rGO (1 wt% GO) significantly improved the photocatalytic activity of rutile TiO2.